An image forming apparatus of one type forms a toner image on an image carrier and transfers the toner image on the image carrier to a recording medium. The image forming apparatus includes a toner adhesion detection unit that detects quantity of toners formed on the image carrier. The image forming apparatus adjusts a bias voltage or the like that is used in forming the toner image on the image carrier based on the quantity of toners detected by the toner amount detection unit.
To transfer the toner image on the image carrier to the recording medium, the image forming apparatus brings the recording medium into pressure contact with the image carrier. The recording medium usually includes a hard additive such as filler. For that reason, if the recording medium comes into pressure contact with image carrier, the additive can minutely damage a surface of the image carrier. If the surface of the image carrier is minutely damaged, accurate detection of the quantity of toners may be compromised. As a result, desired image density may not be obtained.